docs: move more symbols to standard sections
docs: move more symbols to standard sections

Move standard symbols into the standard section.

pwithnall/mx,pwithnall/mx,pwithnall/mx,clutter-project/mx,clutter-project/mx,clutter-project/mx,pwithnall/mx,jonnylamb/mx,clutter-project/mx,jonnylamb/mx,jonnylamb/mx,jonnylamb/mx